Just made my own silencer .......3 pounds lighter

Nate_R

I just experimented making my own silencer. I took off my FMF Q exaust cause it needs repacking. I weighed it and was about 6 1/4 lbs. The stock titanium head pipe is 1/2 lb so that gives me a total weight of 6 3/4 lbs. I'm not sure what the stock WR exhaust weighs, anybody know? I think its like 8 pounds or more. Anyway, I took apart the Q exhaust, and pulled off the can. it was heavy. The mid pipe was
1 1/2 lbs. I used this as a start for my own muffler. I took some thin sheet aluminum from an old dish washer I had junked and used it to make the can. It is fairly thin and would take a couple spills on the bike. Hard crashes would ding it pretty good, though. Anyway, using the Q mid pipe,
I wraped the sheet aluminum around the flange and drilled holes to match up with the midpipe holes. Then I took the spark arretser and slid it in the other end and wraped the aluminum around it. This gave me the oval shape. I took what was left of the original packing and wraped it around the tube with holes in it, inside the can. So basically it is a straight through exhaust. To seal the can, I overlaped it on the back side, ran a generous bead of hightemp rtv, and used sheet metal screws every 2" to close it up. The final weight was 3 lbs!!!! If I redo it with a titanium mid pipe, I think I could shave off another 3/4 pound for sure.
So now my whole exhaust is 3 1/2 pounds, total. I was thinking that power-wise might not work too well ( I was just kinda fooling around building this just to experiment).
So, I fire up the bike. Whoa! It sounds pretty deep. Has a real good sound to it. It's loud, but not nearly as loud as I thought it would be. It only has half of the packing in it, so it should be even quieter when I repack it. Oh the length of my new silencer is 14". So now for the ride.
I take it up the street. It definately revs quicker than the Q. But the Q purposly slows the revs to help with off road traction. It has NOTICEABLY more over-all power than the Q. I was suprised. So I don't think I screwed up too bad. I'm really curious to put it on a dyno and compare the difference thoughout the powerband. I't would be cool if I could try several different designs and gage the gains and loses. Anyway, I'm gonna redo it a little nicer and loose another 3/4 lb off the mid pipe. For me its a keeper!
(until I smash it crashing, and then I 'll build another)
It cost $0 for me to make this scrounging up parts. I'm sure there is a lot more to making an exhaust that I am missing, but I'm going to dyno it and if it performs well, I might make a few of them and sell cheap to freinds. Less than $100.

Nate_R

ddialogue

Nate_R

Some people probly thinks I'm nuts. I love it! I really noticed a weight difference removing the 3 lbs from the exhaust cause it is so high up on the bike. The top of the bike is the most important place to remove weight IMO
(Well, next to rotational mass ). My WR 450 is now so far from being top heavy it's a joke. Feels like a 250 2 smoke. Now....what else can I modify??..............

Nate_R

Thanks again David. By the way..... notice anything different about my front and rear fenders? I trimmed and shortened the front fender 3-4 " and the rear 3-4 ". I'm not sure on the exact measurement, I just did it. Also my side panels got pretty banged up so I trimmed them too. What do you guys think? Should I put new side panels on?
This may sound stupid, but I also trimmed off alot of the fenders under the seat and also the rear part of the front fender. All the fender trimming saved me about 1 1/2 lbs weight. It's all adding up pretty quick.

Nate_R

The only reason it's black is cause that is the color that the dishwasher was. I'll probably make another one that is perfect that is polished or satin. Maybe make my own label for it. That would be cool. What I want to research is just how much back pressure and exhaust flow, exhaust speed, etc. is optimum for the 450.

Nate_R

I know the stock yz pipes are pretty good. It'll still be a pound or 2 heavier than the one I made. Removing a pound here, a pound there is adding up really quick. I went out and rode my bike again. The power with my new pipe is REALLY good. Besides, you can't really compete with free!
I have to say I started out just kinda messing around being
stupid on purpose trying to build one. I figured it would be really loud and obnoxious and people would be like,
"What in the hell is that?!" But I suprised myself, and it actually works really well. Now to the Dyno..........